The present invention relates to a fuel injection timing control device of a fuel injection pump in response to the rotating speed of an internal combustion engine and, more particularly, to a device adapted for a small universal engine.
A device of this type for controlling the fuel injection timing of a fuel injection pump is termed "an automatic timer". This automatic timer serves to advance or delay the injection time of fuel injected into the cylinders of an engine from a fuel injection pump in response to the rotating speed of the engine, and is used such that the pressure in the cylinders reach the maximum value at an optimum time in response to the movement of the piston reciprocating in the cylinder.
An automatic timer, which was disclosed in Japanese Patent Disclosure No. 3617/1979, is known as an automatic timer of this type. This conventional automatic timer is disposed between an engine and a fuel injection pump. In the automatic timer, a driven gear, provided concentrically with one end side of the timer, is engaged in mesh with a drive gear rotated by an engine, while the automatic timer is connected serially to the fuel injection pump cam shaft.
With this conventional automatic timer, applied to a small general engine, the following observations have been made. Engines can be classified into two types according to the position of the drive gear. One of these engines is adapted for an automatic timer having a driven gear at one end as described above, while the other type is adapted for an automatic timer having a driven gear at the other end. Thus, two types of the automatic timers should be required in view of the position of the driven gear. However, in order to manufacture automatic timers of two types drawbacks, such as increased manufacturing cost, error in assembling the parts and complications in managing the exchange of spare parts for the two types of automatic timers arise.